Can you die from pharyngitis?

Yes. There are many different causes of pharyngitis (i.e. infection or inflammation of the pharynx) Depending on the type and if not treated corrected, it can form an abscess and spread to other parts of your throat/mouth/neck and even upper chest. The consequences can be deadly.
Peritonsilar abcess. Peritonsilar abcess, lugwig angina if not treated promptly can compromise your airway and kill you. You'l l kow because you will start drooling, have difficulty swallowing (not just sore throat), your voice may change (gooffy voice), may try to strech your neck in order to get air. Cal 911 if having any of these symptoms.